Title:Tail states in clean superconductors with magnetic impurities

Abstract: We analyse the behavior of the density of states in a singlet s-wave
superconductor with weak magnetic impurities in the clean limit. By using the
method of optimal fluctuation and treating the order parameter
self-consistently we show that the density of states is finite everywhere in
the superconducting gap, and that it varies as $\ln N(E)\propto
-|E-Δ_0|^{(7-d)/4}$ near the mean field gap edge $Δ_0$ in a
d-dimensional superconductor. In contrast to most studied cases the optimal
fluctuation is strongly anisotropic.